A touch-sensing-enabled active matrix LCD panel is an active matrix LCD display having an additional function of detecting a location of a possible touch made on the panel. The detection may be accomplished by an electrostatic capacitance method. This method is herein referred to as an in-cell self-capacitive touch sensing method.
In the implementation of the in-cell self-capacitive touch sensing method, additional touch sensing channels are required to be integrated into a display driver IC. This two-in-one IC is called a TDDI chip. These additional touch sensing channels may go up to 500 for a five-inch display. For such large number of touch sensing channels, it increases the overall number of pads of the TDDI chip to a level that significantly increases the IC packaging and testing costs.
In U.S. Pat. No. 8,760,412, it is disclosed a display having data lines that can be configured between a display mode and a touch mode. In European Patent No. 1,455,264, it is suggested a driver IC using an active matrix as a means of input such that the display and sensing functions are integrated without a need to modify the active matrix, thereby indirectly reducing a pin count. Despite various efforts in the art for reducing the pin count of a TDDI chip, there is still a need for an improved method and apparatus to further reduce the pin count.